package mcp

import (
	"context"
	"encoding/json"
	"fmt"

	"github.com/mathiasbq/hyperguild/ingestion/internal/capturehttp"
)

// principalKey is the context key under which the authenticated principal
// (re-derived in ServeHTTP) is stashed for the capture tool.
type principalKeyT struct{}

var principalKey principalKeyT

type principalInfo struct {
	principal string
	viaStatic bool
}

func withPrincipal(ctx context.Context, principal string, viaStatic bool) context.Context {
	return context.WithValue(ctx, principalKey, principalInfo{principal: principal, viaStatic: viaStatic})
}

// captureToolDescriptor is the tools/list entry for the capture relay.
// Appended only when WithCapture has wired the tool.
func captureToolDescriptor() map[string]any {
	str := func(d string) map[string]any { return map[string]any{"type": "string", "description": d} }
	insightItem := map[string]any{
		"type": "object",
		"properties": map[string]any{
			"text": str("the insight body"), "wing": str("brain wing"),
			"hall": str("brain hall (facts/decisions/failures/hypotheses/sources)"),
			"supersede_slug": str("optional: slug of a prior note to revise in place instead of creating"),
		},
		"required": []string{"text", "wing", "hall"},
	}
	ticketItem := map[string]any{
		"type": "object",
		"properties": map[string]any{
			"repo": str("gitea repo (owner is always mathias)"), "action": str("create|close|comment"),
			"number": map[string]any{"type": "integer", "description": "issue number (close/comment)"},
			"title": str("issue title (create)"), "body": str("issue/comment body"),
		},
		"required": []string{"repo", "action"},
	}
	schema := map[string]any{
		"type": "object",
		"properties": map[string]any{
			"context": map[string]any{
				"type": "object",
				"properties": map[string]any{
					"harness": str("descriptive harness label (telemetry only, never a gate input)"),
					"session_ref": str("optional session reference"), "fidelity": str("live-capture|transcript-parse|agent-runlog"),
					"actor": str("acting user/agent"), "classification": str("caller-declared sensitivity: public|internal|confidential"),
				},
			},
			"insights": map[string]any{"type": "array", "items": insightItem},
			"tickets":  map[string]any{"type": "array", "items": ticketItem},
			"dry_run": map[string]any{"type": "boolean", "description": "validate + return the would-be receipt, write nothing"},
		},
	}
	b, _ := json.Marshal(schema)
	return map[string]any{
		"name":        "capture",
		"description": "Persist a session's value uniformly: insights → brain (write or supersede), action items → Gitea tickets. The relay door for MCP-native harnesses. Origin is server-derived from your authenticated identity; confidential captures through a us-nexus surface are refused (I1). Returns a partial-aware receipt.",
		"inputSchema": json.RawMessage(b),
	}
}

// brainCapture is the MCP capture tool: the #55 relay for MCP-native
// harnesses. It re-uses the same CaptureService, principal-derivation, and
// origin resolver as POST /capture — only the transport differs. It holds
// no state and retains nothing beyond the I5 audit record.
func (s *Server) brainCapture(ctx context.Context, args json.RawMessage) (json.RawMessage, error) {
	if s.capture == nil {
		return nil, fmt.Errorf("capture tool not configured")
	}
	info, ok := ctx.Value(principalKey).(principalInfo)
	if !ok || info.principal == "" {
		// No authenticated principal ⇒ cannot derive origin ⇒ cannot gate.
		return nil, fmt.Errorf("capture requires an authenticated principal")
	}

	in, err := capturehttp.DecodeRequest(args)
	if err != nil {
		return nil, fmt.Errorf("invalid capture request: %w", err)
	}
	// Principal and origin are server-derived — never taken from the body.
	in.Context.Principal = info.principal
	in.Context.Origin = s.capture.resolver.Resolve(info.principal, info.viaStatic)

	rec, err := s.capture.svc.Capture(ctx, in)
	if err != nil {
		// Surface I1/I5 refusals and validation failures verbatim; errors.Is
		// markers (ErrSovereigntyRefused / ErrAuditUnavailable) ride in the message.
		return nil, err
	}
	return json.Marshal(rec)
}