// Package ipc is the protocol between mitmuxd (which owns the proxy and
// the history database) and a client such as the TUI, spoken as
// newline-agnostic JSON messages over a Unix domain socket. This keeps
// the proxy engine running independently of any UI attached to it.
package ipc

import (
	"encoding/json"
	"errors"
	"fmt"
	"net"
	"sync"
	"time"

	"mitmux/internal/clientcert"
	"mitmux/internal/proxy"
	"mitmux/internal/rules"
	"mitmux/internal/scope"
	"mitmux/internal/store"
)

// Request is sent by a client to the daemon.
type Request struct {
	Type     string `json:"type"` // "list", "get", "subscribe", "repeat", "intrude", "rules_list", "rules_save", "rules_delete", "rules_toggle", "delete_entry", or "clear_history"
	Limit    int    `json:"limit,omitempty"`
	BeforeID int64  `json:"before_id,omitempty"`
	ID       int64  `json:"id,omitempty"`

	// For "list": a non-empty Query switches from most-recent-first to
	// an FTS5 search (see store.Store.Search for syntax), ranked by
	// relevance.
	Query string `json:"query,omitempty"`

	// For "repeat": send Raw to scheme://host exactly as given.
	// For "intrude": Raw is the §marked§ template - see proxy.Intrude.
	Scheme string `json:"scheme,omitempty"`
	Host   string `json:"host,omitempty"`
	Raw    []byte `json:"raw,omitempty"`

	// For "intrude": the attack mode (proxy.Sniper and so on - empty
	// defaults to Sniper) and its payload sets. Sniper and BatteringRam
	// only ever use PayloadSets[0] (one shared set); Pitchfork and
	// ClusterBomb require exactly one set per §marked§ position, in
	// order - see proxy.Intrude.
	Mode        proxy.AttackMode `json:"mode,omitempty"`
	PayloadSets [][]string       `json:"payload_sets,omitempty"`

	// For "intrude": optional Go regexps evaluated against each result's
	// response bytes. GrepMatch flags whether it matched at all;
	// GrepExtract additionally captures text (first submatch if the
	// pattern has a capturing group, else the whole match) into the
	// result. Either or both may be empty to skip that check. Compiled
	// and validated once, server-side, before the attack starts - a bad
	// pattern fails the same way a bad marker or empty payload set does.
	GrepMatch   string `json:"grep_match,omitempty"`
	GrepExtract string `json:"grep_extract,omitempty"`

	// For "rules_save": add (Rule.ID == 0) or update (Rule.ID != 0) a
	// match-and-replace rule. For "rules_delete"/"rules_toggle": RuleID
	// (and RuleEnabled for toggle) identify the target.
	Rule        *rules.Rule `json:"rule,omitempty"`
	RuleID      int64       `json:"rule_id,omitempty"`
	RuleEnabled bool        `json:"rule_enabled,omitempty"`

	// For "scope_add": the new rule (always an add - scope rules are
	// simple enough that edit-in-place isn't worth a separate update
	// path; delete and re-add covers it). For "scope_delete"/
	// "scope_toggle": ScopeRuleID (and RuleEnabled for toggle) identify
	// the target.
	ScopeRule   *scope.Rule `json:"scope_rule,omitempty"`
	ScopeRuleID int64       `json:"scope_rule_id,omitempty"`

	// For "clientcert_add": the new certificate (always an add, same
	// reasoning as scope rules above). For "clientcert_delete"/
	// "clientcert_toggle": ClientCertID (and RuleEnabled for toggle)
	// identify the target.
	ClientCert   *clientcert.Cert `json:"client_cert,omitempty"`
	ClientCertID int64            `json:"client_cert_id,omitempty"`

	// For "tag_entry": ID identifies the history entry (same field
	// "get"/"set_flagged"/"delete_entry" use). Plugin names who's
	// tagging it - informational only, not an identity or auth
	// mechanism, since anything that can reach the socket can claim any
	// name. Tag is the short marker itself (e.g. "jwt", "authz-bypass").
	// Data is an opaque, plugin-defined JSON blob a panel view renders
	// later without needing this plugin still connected - empty is
	// fine for a plugin that only needs the tag itself, no extra detail.
	TagPlugin string `json:"tag_plugin,omitempty"`
	Tag       string `json:"tag,omitempty"`
	TagData   string `json:"tag_data,omitempty"`

	// For "set_flagged" and "delete_entry": ID identifies the history
	// entry. "clear_history" needs no fields at all.
	Flagged bool `json:"flagged,omitempty"`

	// For "import": entries to insert directly into history - the
	// client has already parsed/converted them (e.g. from a HAR file,
	// see cmd/mitmux/har.go); the daemon just stores them.
	ImportEntries []ImportEntry `json:"import_entries,omitempty"`
}

// ImportEntry is one entry to insert directly into history via
// "import". RequestExact/ResponseExact are always false once stored:
// an imported entry is reconstructed from whatever structured format it
// came from (HAR, say), never the literal bytes that were on the wire
// for the original request - the same situation an HTTP/2 capture is
// already in.
type ImportEntry struct {
	Method      string        `json:"method"`
	Scheme      string        `json:"scheme"`
	Host        string        `json:"host"`
	Path        string        `json:"path"`
	StatusCode  int           `json:"status_code"`
	RequestRaw  []byte        `json:"request_raw"`
	ResponseRaw []byte        `json:"response_raw"`
	StartedAt   time.Time     `json:"started_at"`
	Duration    time.Duration `json:"duration"`
}

// Response is sent by the daemon to a client.
type Response struct {
	Type        string            `json:"type"`                   // "list", "get", "new", "repeat", "rules", "scope_rules", "intrude_result", "intrude_done", "import_done", "status", "flagged", "deleted", "cleared", or "error"
	Entries     []store.Summary   `json:"entries,omitempty"`      // for "list"
	Detail      *EntryDetail      `json:"detail,omitempty"`       // for "get" and "repeat"
	New         *store.Summary    `json:"new,omitempty"`          // for "new" (subscribe push)
	Rules       []rules.Rule      `json:"rules,omitempty"`        // for "rules"
	ScopeRules  []scope.Rule      `json:"scope_rules,omitempty"`  // for "scope_rules"
	ClientCerts []clientcert.Cert `json:"client_certs,omitempty"` // for "client_certs"
	WSMessages  []store.WSMessage `json:"ws_messages,omitempty"`  // for "ws_messages"
	Status      *StatusMsg        `json:"status,omitempty"`       // for "status"

	// For "import_done": how many entries were actually inserted (a
	// per-entry insert failure is skipped, not fatal to the batch).
	Imported int `json:"imported,omitempty"`

	// For "tag_entry": the new tag row's assigned ID.
	TagID int64 `json:"tag_id,omitempty"`

	// For "intrude_result": one completed attack request.
	IntrudeResult *IntrudeResultMsg `json:"intrude_result,omitempty"`

	Error string `json:"error,omitempty"`
}

// StatusMsg is basic daemon info for a TUI status bar.
type StatusMsg struct {
	ProxyAddr    string `json:"proxy_addr"`
	HistoryCount int64  `json:"history_count"`
}

// IntrudeResultMsg is one completed Intruder attack request. Values holds
// what was substituted into each §marked§ position for this request, in
// position order - for Sniper, every entry but the one fuzzed position
// equals that position's base value; for the other three modes every
// entry is an actual payload.
type IntrudeResultMsg struct {
	Iteration   int           `json:"iteration"`
	Values      []string      `json:"values"`
	EntryID     int64         `json:"entry_id"`
	StatusCode  int           `json:"status_code"`
	RespSize    int           `json:"resp_size"`
	Duration    time.Duration `json:"duration"`
	Error       string        `json:"error,omitempty"`
	GrepMatch   bool          `json:"grep_match,omitempty"`
	GrepExtract string        `json:"grep_extract,omitempty"`
}

// EntryDetail is a full history entry, raw bytes included.
type EntryDetail struct {
	store.Summary
	RequestRaw    []byte `json:"request_raw"`
	ResponseRaw   []byte `json:"response_raw"`
	RequestExact  bool   `json:"request_exact"`
	ResponseExact bool   `json:"response_exact"`
	// *Truncated is true when the matching *Exact is false specifically
	// because capture hit its size cap and dropped bytes off the end -
	// as opposed to false because there was never a wire-exact
	// representation to begin with (HTTP/2). Only meaningful alongside
	// a false *Exact.
	RequestTruncated  bool `json:"request_truncated,omitempty"`
	ResponseTruncated bool `json:"response_truncated,omitempty"`
	// Tags is every plugin-contributed marker on this entry - see the
	// "tag_entry" request. Summary.Tags (from List/Search) is just the
	// comma-joined names for a compact list-view badge; this is the
	// full record, including each tag's plugin and opaque Data blob, for
	// a panel view to render.
	Tags []store.EntryTag `json:"tags,omitempty"`
}

// Client talks to a mitmuxd instance for request/response queries
// (list, get). Use Subscribe separately for the live-update stream.
//
// One request/response round trip is in flight on the connection at a
// time, guarded by mu - a caller like the mitmux TUI dispatches each
// request as its own goroutine (a Bubble Tea tea.Cmd), and without this
// two overlapping calls (e.g. opening two entries in quick succession)
// would interleave their JSON on the wire or hand one call the other's
// response.
type Client struct {
	mu   sync.Mutex
	conn net.Conn
	dec  *json.Decoder
	enc  *json.Encoder
}

// Dial connects to the daemon's control socket at path.
func Dial(path string) (*Client, error) {
	conn, err := net.Dial("unix", path)
	if err != nil {
		return nil, fmt.Errorf("dial %s: %w", path, err)
	}
	return &Client{conn: conn, dec: json.NewDecoder(conn), enc: json.NewEncoder(conn)}, nil
}

// Close closes the connection to the daemon.
func (c *Client) Close() error {
	return c.conn.Close()
}

// SetFlagged sets the flagged marker on a history entry - a simple
// "mark this, revisit later" bit, filterable via flagged:true/false in
// Search.
// TagEntry marks history entry id with tag, attributed to plugin (any
// non-empty name a plugin chooses to identify itself by - informational
// only), with an optional opaque data blob a panel view can render
// later. This is the core plugin-integration primitive: any process
// that can reach the control socket - the reference Go client here, or
// a plugin in any other language following the same JSON wire protocol
// (see PLAN.md) - can tag entries it finds interesting without mitmux
// needing to know anything about it in advance. Returns the new tag's
// assigned ID.
func (c *Client) TagEntry(entryID int64, plugin, tag, data string) (int64, error) {
	c.mu.Lock()
	defer c.mu.Unlock()
	if err := c.enc.Encode(Request{Type: "tag_entry", ID: entryID, TagPlugin: plugin, Tag: tag, TagData: data}); err != nil {
		return 0, err
	}
	var resp Response
	if err := c.dec.Decode(&resp); err != nil {
		return 0, err
	}
	if resp.Type == "error" {
		return 0, errors.New(resp.Error)
	}
	return resp.TagID, nil
}

func (c *Client) SetFlagged(id int64, flagged bool) error {
	c.mu.Lock()
	defer c.mu.Unlock()
	if err := c.enc.Encode(Request{Type: "set_flagged", ID: id, Flagged: flagged}); err != nil {
		return err
	}
	var resp Response
	if err := c.dec.Decode(&resp); err != nil {
		return err
	}
	if resp.Type == "error" {
		return errors.New(resp.Error)
	}
	return nil
}

// DeleteEntry removes a single history entry.
func (c *Client) DeleteEntry(id int64) error {
	c.mu.Lock()
	defer c.mu.Unlock()
	if err := c.enc.Encode(Request{Type: "delete_entry", ID: id}); err != nil {
		return err
	}
	var resp Response
	if err := c.dec.Decode(&resp); err != nil {
		return err
	}
	if resp.Type == "error" {
		return errors.New(resp.Error)
	}
	return nil
}

// ClearHistory removes every history entry. Rules are untouched.
func (c *Client) ClearHistory() error {
	c.mu.Lock()
	defer c.mu.Unlock()
	if err := c.enc.Encode(Request{Type: "clear_history"}); err != nil {
		return err
	}
	var resp Response
	if err := c.dec.Decode(&resp); err != nil {
		return err
	}
	if resp.Type == "error" {
		return errors.New(resp.Error)
	}
	return nil
}

// Import inserts entries directly into history - used to bring in
// traffic from an external source (a HAR file, say) rather than
// something mitmux itself captured. Returns how many were actually
// inserted; a per-entry insert failure is skipped rather than aborting
// the whole batch.
func (c *Client) Import(entries []ImportEntry) (int, error) {
	c.mu.Lock()
	defer c.mu.Unlock()
	if err := c.enc.Encode(Request{Type: "import", ImportEntries: entries}); err != nil {
		return 0, err
	}
	var resp Response
	if err := c.dec.Decode(&resp); err != nil {
		return 0, err
	}
	if resp.Type == "error" {
		return 0, errors.New(resp.Error)
	}
	return resp.Imported, nil
}

// Status returns basic daemon info for a status bar.
func (c *Client) Status() (*StatusMsg, error) {
	c.mu.Lock()
	defer c.mu.Unlock()
	if err := c.enc.Encode(Request{Type: "status"}); err != nil {
		return nil, err
	}
	var resp Response
	if err := c.dec.Decode(&resp); err != nil {
		return nil, err
	}
	if resp.Type == "error" {
		return nil, errors.New(resp.Error)
	}
	return resp.Status, nil
}

// List returns up to limit history summaries older than beforeID (0 for
// the most recent), newest first.
func (c *Client) List(limit int, beforeID int64) ([]store.Summary, error) {
	return c.list(Request{Type: "list", Limit: limit, BeforeID: beforeID})
}

// Search returns up to limit history summaries matching an FTS5 query
// (see store.Store.Search for syntax), ranked by relevance.
func (c *Client) Search(query string, limit int, beforeID int64) ([]store.Summary, error) {
	return c.list(Request{Type: "list", Query: query, Limit: limit, BeforeID: beforeID})
}

func (c *Client) list(req Request) ([]store.Summary, error) {
	c.mu.Lock()
	defer c.mu.Unlock()
	if err := c.enc.Encode(req); err != nil {
		return nil, err
	}
	var resp Response
	if err := c.dec.Decode(&resp); err != nil {
		return nil, err
	}
	if resp.Type == "error" {
		return nil, errors.New(resp.Error)
	}
	return resp.Entries, nil
}

// Get returns the full entry (raw bytes included) for id.
func (c *Client) Get(id int64) (*EntryDetail, error) {
	c.mu.Lock()
	defer c.mu.Unlock()
	if err := c.enc.Encode(Request{Type: "get", ID: id}); err != nil {
		return nil, err
	}
	var resp Response
	if err := c.dec.Decode(&resp); err != nil {
		return nil, err
	}
	if resp.Type == "error" {
		return nil, errors.New(resp.Error)
	}
	return resp.Detail, nil
}

// ListWSMessages returns every WebSocket frame captured for entryID's
// connection, in the order they were sent - empty (not an error) if the
// entry wasn't a WebSocket upgrade or nothing was captured.
func (c *Client) ListWSMessages(entryID int64) ([]store.WSMessage, error) {
	c.mu.Lock()
	defer c.mu.Unlock()
	if err := c.enc.Encode(Request{Type: "ws_messages", ID: entryID}); err != nil {
		return nil, err
	}
	var resp Response
	if err := c.dec.Decode(&resp); err != nil {
		return nil, err
	}
	if resp.Type == "error" {
		return nil, errors.New(resp.Error)
	}
	return resp.WSMessages, nil
}

// Repeat sends raw to scheme://host exactly as given (no re-serialization,
// no header injection) and returns the resulting entry, including the raw
// response bytes. The exchange is also recorded to history.
func (c *Client) Repeat(scheme, host string, raw []byte) (*EntryDetail, error) {
	c.mu.Lock()
	defer c.mu.Unlock()
	if err := c.enc.Encode(Request{Type: "repeat", Scheme: scheme, Host: host, Raw: raw}); err != nil {
		return nil, err
	}
	var resp Response
	if err := c.dec.Decode(&resp); err != nil {
		return nil, err
	}
	if resp.Type == "error" {
		return nil, errors.New(resp.Error)
	}
	return resp.Detail, nil
}

// ListRules returns every match-and-replace rule.
func (c *Client) ListRules() ([]rules.Rule, error) {
	c.mu.Lock()
	defer c.mu.Unlock()
	return c.rulesRoundTrip(Request{Type: "rules_list"})
}

// SaveRule adds r (if r.ID == 0) or updates the existing rule with that
// ID, and returns its ID.
func (c *Client) SaveRule(r rules.Rule) (int64, error) {
	c.mu.Lock()
	defer c.mu.Unlock()
	saved, err := c.rulesRoundTrip(Request{Type: "rules_save", Rule: &r})
	if err != nil {
		return 0, err
	}
	if len(saved) == 0 {
		return 0, errors.New("rules_save: daemon returned no rule")
	}
	return saved[0].ID, nil
}

// DeleteRule removes a rule.
func (c *Client) DeleteRule(id int64) error {
	c.mu.Lock()
	defer c.mu.Unlock()
	_, err := c.rulesRoundTrip(Request{Type: "rules_delete", RuleID: id})
	return err
}

// SetRuleEnabled toggles a rule without touching its other fields.
func (c *Client) SetRuleEnabled(id int64, enabled bool) error {
	c.mu.Lock()
	defer c.mu.Unlock()
	_, err := c.rulesRoundTrip(Request{Type: "rules_toggle", RuleID: id, RuleEnabled: enabled})
	return err
}

func (c *Client) rulesRoundTrip(req Request) ([]rules.Rule, error) {
	if err := c.enc.Encode(req); err != nil {
		return nil, err
	}
	var resp Response
	if err := c.dec.Decode(&resp); err != nil {
		return nil, err
	}
	if resp.Type == "error" {
		return nil, errors.New(resp.Error)
	}
	return resp.Rules, nil
}

// ListScopeRules returns every scope rule, enabled or not.
func (c *Client) ListScopeRules() ([]scope.Rule, error) {
	c.mu.Lock()
	defer c.mu.Unlock()
	return c.scopeRoundTrip(Request{Type: "scope_list"})
}

// AddScopeRule adds r and returns its assigned ID.
func (c *Client) AddScopeRule(r scope.Rule) (int64, error) {
	c.mu.Lock()
	defer c.mu.Unlock()
	saved, err := c.scopeRoundTrip(Request{Type: "scope_add", ScopeRule: &r})
	if err != nil {
		return 0, err
	}
	if len(saved) == 0 {
		return 0, errors.New("scope_add: daemon returned no rule")
	}
	return saved[0].ID, nil
}

// DeleteScopeRule removes a scope rule.
func (c *Client) DeleteScopeRule(id int64) error {
	c.mu.Lock()
	defer c.mu.Unlock()
	_, err := c.scopeRoundTrip(Request{Type: "scope_delete", ScopeRuleID: id})
	return err
}

// SetScopeRuleEnabled toggles a scope rule without touching its pattern.
func (c *Client) SetScopeRuleEnabled(id int64, enabled bool) error {
	c.mu.Lock()
	defer c.mu.Unlock()
	_, err := c.scopeRoundTrip(Request{Type: "scope_toggle", ScopeRuleID: id, RuleEnabled: enabled})
	return err
}

func (c *Client) scopeRoundTrip(req Request) ([]scope.Rule, error) {
	if err := c.enc.Encode(req); err != nil {
		return nil, err
	}
	var resp Response
	if err := c.dec.Decode(&resp); err != nil {
		return nil, err
	}
	if resp.Type == "error" {
		return nil, errors.New(resp.Error)
	}
	return resp.ScopeRules, nil
}

// ListClientCerts returns every client certificate, enabled or not.
func (c *Client) ListClientCerts() ([]clientcert.Cert, error) {
	c.mu.Lock()
	defer c.mu.Unlock()
	return c.clientCertRoundTrip(Request{Type: "clientcert_list"})
}

// AddClientCert adds cert and returns its assigned ID.
func (c *Client) AddClientCert(cert clientcert.Cert) (int64, error) {
	c.mu.Lock()
	defer c.mu.Unlock()
	saved, err := c.clientCertRoundTrip(Request{Type: "clientcert_add", ClientCert: &cert})
	if err != nil {
		return 0, err
	}
	if len(saved) == 0 {
		return 0, errors.New("clientcert_add: daemon returned no certificate")
	}
	return saved[0].ID, nil
}

// DeleteClientCert removes a client certificate.
func (c *Client) DeleteClientCert(id int64) error {
	c.mu.Lock()
	defer c.mu.Unlock()
	_, err := c.clientCertRoundTrip(Request{Type: "clientcert_delete", ClientCertID: id})
	return err
}

// SetClientCertEnabled toggles a client cert without touching its
// content.
func (c *Client) SetClientCertEnabled(id int64, enabled bool) error {
	c.mu.Lock()
	defer c.mu.Unlock()
	_, err := c.clientCertRoundTrip(Request{Type: "clientcert_toggle", ClientCertID: id, RuleEnabled: enabled})
	return err
}

func (c *Client) clientCertRoundTrip(req Request) ([]clientcert.Cert, error) {
	if err := c.enc.Encode(req); err != nil {
		return nil, err
	}
	var resp Response
	if err := c.dec.Decode(&resp); err != nil {
		return nil, err
	}
	if resp.Type == "error" {
		return nil, errors.New(resp.Error)
	}
	return resp.ClientCerts, nil
}

// Subscribe opens a dedicated connection that streams newly captured
// history entries as they happen. The returned channel is closed when
// the connection ends; call the returned close func to stop early.
func Subscribe(path string) (<-chan store.Summary, func() error, error) {
	conn, err := net.Dial("unix", path)
	if err != nil {
		return nil, nil, fmt.Errorf("dial %s: %w", path, err)
	}
	if err := json.NewEncoder(conn).Encode(Request{Type: "subscribe"}); err != nil {
		conn.Close()
		return nil, nil, err
	}

	ch := make(chan store.Summary, 64)
	go func() {
		defer close(ch)
		dec := json.NewDecoder(conn)
		for {
			var resp Response
			if err := dec.Decode(&resp); err != nil {
				return
			}
			if resp.Type == "new" && resp.New != nil {
				select {
				case ch <- *resp.New:
				default:
				}
			}
		}
	}()
	return ch, conn.Close, nil
}

// Intrude starts an attack (see proxy.Intrude and proxy.AttackMode):
// template must contain at least one §marked§ position. mode selects how
// payloadSets combine across positions; "" defaults to Sniper.
// grepMatch/grepExtract are optional Go regexps evaluated server-side
// against each result's response bytes (empty string disables either
// check) - see IntrudeResultMsg. Unlike Subscribe's live feed, no result
// is ever dropped for a slow consumer - each one is the attack's actual
// data, not a notification with the real thing recoverable elsewhere. A
// setup error (bad markers, empty payload set, too many requests, an
// unparseable grep regexp) is returned directly rather than through the
// channel. The returned channel closes when the attack finishes or the
// connection is closed early.
func Intrude(path, scheme, host string, template []byte, mode proxy.AttackMode, payloadSets [][]string, grepMatch, grepExtract string) (<-chan IntrudeResultMsg, func() error, error) {
	conn, err := net.Dial("unix", path)
	if err != nil {
		return nil, nil, fmt.Errorf("dial %s: %w", path, err)
	}
	req := Request{Type: "intrude", Scheme: scheme, Host: host, Raw: template, Mode: mode, PayloadSets: payloadSets, GrepMatch: grepMatch, GrepExtract: grepExtract}
	if err := json.NewEncoder(conn).Encode(req); err != nil {
		conn.Close()
		return nil, nil, err
	}

	dec := json.NewDecoder(conn)
	var first Response
	if err := dec.Decode(&first); err != nil {
		conn.Close()
		return nil, nil, err
	}
	if first.Type == "error" {
		conn.Close()
		return nil, nil, errors.New(first.Error)
	}

	ch := make(chan IntrudeResultMsg)
	go func() {
		defer close(ch)
		deliver := func(resp Response) bool {
			switch resp.Type {
			case "intrude_result":
				if resp.IntrudeResult != nil {
					ch <- *resp.IntrudeResult
				}
				return true
			default: // "intrude_done", or anything else - stop
				return false
			}
		}
		if !deliver(first) {
			return
		}
		for {
			var resp Response
			if err := dec.Decode(&resp); err != nil {
				return
			}
			if !deliver(resp) {
				return
			}
		}
	}()
	return ch, conn.Close, nil
}