feat(discovery): add Pass 0 agent client + parser (Mistral)

backend/internal/domain/discovery/agent_client.go

@@ -0,0 +1,115 @@
+package discovery
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"marktvogt.de/backend/internal/pkg/ai"
+)
+
+// AgentClient wraps the Mistral Pass 0 agent for discovery.
+type AgentClient struct {
+	ai      *ai.Client
+	agentID string
+}
+
+func NewAgentClient(aiClient *ai.Client, agentID string) *AgentClient {
+	return &AgentClient{ai: aiClient, agentID: agentID}
+}
+
+func (c *AgentClient) Enabled() bool {
+	return c.ai != nil && c.agentID != ""
+}
+
+// Discover runs Pass 0 for the given bucket. The agent's full instructions
+// are set in the Mistral console (see spec §6.2). We only inject the bucket
+// parameters here.
+func (c *AgentClient) Discover(ctx context.Context, b Bucket) (Pass0Response, error) {
+	if !c.Enabled() {
+		return Pass0Response{}, fmt.Errorf("discovery agent not configured")
+	}
+	prompt := fmt.Sprintf(
+		"Bucket:\nland: %s\nregion: %s\njahr_monat: %s\n\nFinde alle Maerkte in diesem Bucket und antworte im vorgegebenen JSON-Format.",
+		b.Land, b.Region, b.YearMonth,
+	)
+	result, err := c.ai.Pass0(ctx, c.agentID, prompt)
+	if err != nil {
+		return Pass0Response{}, fmt.Errorf("mistral pass0: %w", err)
+	}
+	return parsePass0Response(result.Content)
+}
+
+func parsePass0Response(raw string) (Pass0Response, error) {
+	cleaned := extractJSON(raw)
+	cleaned = stripJSONComments(cleaned)
+	var out Pass0Response
+	if err := json.Unmarshal([]byte(cleaned), &out); err != nil {
+		return Pass0Response{}, fmt.Errorf("unmarshal pass0: %w (raw first 500: %q)", err, truncate(raw, 500))
+	}
+	return out, nil
+}
+
+// --- JSON helpers (independent copy; logic mirrors domain/market/research.go).
+// Do not import from the market package — keeping packages decoupled.
+
+func extractJSON(s string) string {
+	start := strings.IndexByte(s, '{')
+	if start < 0 {
+		return s
+	}
+	s = s[start:]
+	depth := 0
+	for i := 0; i < len(s); i++ {
+		switch s[i] {
+		case '{':
+			depth++
+		case '}':
+			depth--
+			if depth == 0 {
+				return s[:i+1]
+			}
+		}
+	}
+	return s
+}
+
+func stripJSONComments(s string) string {
+	var result []byte
+	inString := false
+	escaped := false
+	for i := 0; i < len(s); i++ {
+		c := s[i]
+		if escaped {
+			result = append(result, c)
+			escaped = false
+			continue
+		}
+		if c == '\\' && inString {
+			result = append(result, c)
+			escaped = true
+			continue
+		}
+		if c == '"' {
+			inString = !inString
+			result = append(result, c)
+			continue
+		}
+		if !inString && c == '/' && i+1 < len(s) && s[i+1] == '/' {
+			for i < len(s) && s[i] != '\n' {
+				i++
+			}
+			continue
+		}
+		result = append(result, c)
+	}
+	return string(result)
+}
+
+func truncate(s string, n int) string {
+	if len(s) <= n {
+		return s
+	}
+	return s[:n]
+}

backend/internal/domain/discovery/agent_client_test.go

@@ -0,0 +1,74 @@
+package discovery
+
+import "testing"
+
+func TestParsePass0_Valid(t *testing.T) {
+	raw := `{
+  "bucket": {"land": "Deutschland", "region": "Bayern", "jahr_monat": "2026-09"},
+  "recherche_datum": "2026-04-18",
+  "quellen_gesamt": ["https://a.example", "https://b.example"],
+  "maerkte": [
+    {
+      "markt_name": "Mittelaltermarkt Trostberg",
+      "stadt": "Trostberg",
+      "bundesland": "Bayern",
+      "start_datum": "2026-09-12",
+      "end_datum": "2026-09-14",
+      "website": "https://trostberg.example",
+      "quellen": ["https://a.example"],
+      "extraktion": "verbatim",
+      "hinweis": null
+    }
+  ]
+}`
+	got, err := parsePass0Response(raw)
+	if err != nil {
+		t.Fatalf("parse err: %v", err)
+	}
+	if got.Bucket.Region != "Bayern" {
+		t.Errorf("region = %q, want Bayern", got.Bucket.Region)
+	}
+	if len(got.Maerkte) != 1 || got.Maerkte[0].MarktName != "Mittelaltermarkt Trostberg" {
+		t.Errorf("unexpected markets: %+v", got.Maerkte)
+	}
+}
+
+func TestParsePass0_WithCommentsAndTrailingText(t *testing.T) {
+	raw := `Here is the JSON:
+{
+  "bucket": {"land": "Deutschland", "region": "Bayern", "jahr_monat": "2026-09"},
+  // a comment the agent added
+  "recherche_datum": "2026-04-18",
+  "quellen_gesamt": [],
+  "maerkte": []
+}
+end.`
+	got, err := parsePass0Response(raw)
+	if err != nil {
+		t.Fatalf("parse err: %v", err)
+	}
+	if got.Bucket.Region != "Bayern" || len(got.Maerkte) != 0 {
+		t.Errorf("unexpected: %+v", got)
+	}
+}
+
+func TestParsePass0_Malformed(t *testing.T) {
+	raw := `not JSON at all`
+	if _, err := parsePass0Response(raw); err == nil {
+		t.Error("expected error on non-JSON input")
+	}
+}
+
+func TestParsePass0_EmptyMaerkte(t *testing.T) {
+	raw := `{"bucket":{"land":"Deutschland","region":"Bayern","jahr_monat":"2026-09"},"recherche_datum":"","quellen_gesamt":[],"maerkte":[]}`
+	got, err := parsePass0Response(raw)
+	if err != nil {
+		t.Fatalf("parse err: %v", err)
+	}
+	if got.Maerkte == nil {
+		got.Maerkte = []Pass0Market{} // nil vs empty is fine
+	}
+	if len(got.Maerkte) != 0 {
+		t.Errorf("expected empty, got %+v", got.Maerkte)
+	}
+}

backend/internal/pkg/ai/client.go

@@ -112,6 +112,36 @@ func (c *Client) Pass1(ctx context.Context, prompt string) (PassResult, error) {
 	}, nil
 }
 
+// Pass0 uses the Conversations API to call a discovery agent identified by agentID.
+// The agent ID is passed explicitly so the discovery domain can configure its own
+// agent independently of the agentSimple field used by Pass1.
+func (c *Client) Pass0(ctx context.Context, agentID, prompt string) (PassResult, error) {
+	c.limiter.wait()
+	if c.sdk == nil || agentID == "" {
+		return PassResult{}, fmt.Errorf("pass0: ai client not configured (sdk=%v agentID=%q)", c.sdk != nil, agentID)
+	}
+	storeFalse := false
+	resp, err := c.sdk.StartConversation(ctx, &conversation.StartRequest{
+		AgentID: agentID,
+		Inputs:  conversation.TextInputs(prompt),
+		Store:   &storeFalse,
+	})
+	if err != nil {
+		return PassResult{}, fmt.Errorf("pass0 conversation: %w", err)
+	}
+
+	content := extractConversationContent(resp)
+	if content == "" {
+		return PassResult{}, fmt.Errorf("pass0: no assistant message in response")
+	}
+
+	return PassResult{
+		Content: content,
+		Usage:   convertConvUsage(resp.Usage),
+		Model:   "agent:" + agentID,
+	}, nil
+}
+
 // Pass2 uses chat completions for description generation + retry fields.
 func (c *Client) Pass2(ctx context.Context, systemPrompt, userPrompt string) (PassResult, error) {
 	c.limiter.wait()