package main

import (
	"crypto/rand"
	"encoding/hex"
	"encoding/json"
	"errors"
	"net/http"
	"time"
)

// POST /proposals: the AI VM registers a layer-2 proposal (design 6.5). Response carries the approval token that the
// Discord approval hands back; approved=true in the body records the approval directly (used by tests and by the AI VM
// after the button round-trip). Execution then goes through /actions/execute with that token.
type ProposalRequest struct {
	RunID      *string        `json:"run_id"`
	ScenarioID *string        `json:"scenario_id"`
	ActionID   string         `json:"action_id"`
	Target     map[string]any `json:"target"`
	Diagnosis  map[string]any `json:"diagnosis"`
	Approved   bool           `json:"approved"`
	ApprovedBy string         `json:"approved_by"`
	TTLSeconds int            `json:"ttl_seconds"`
}

func (a *App) handleProposal(w http.ResponseWriter, r *http.Request) {
	var req ProposalRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeErr(w, 400, err)
		return
	}
	if catalogEntry(req.ActionID) == nil {
		writeErr(w, 400, errors.New("action_id not in the catalogue"))
		return
	}
	if cur := a.runs.current(); cur != nil && req.RunID == nil {
		req.RunID = &cur.RunID
		if cur.ScenarioID != "" {
			req.ScenarioID = &cur.ScenarioID
		}
	}
	ttl := 15 * time.Minute // design 2.1: no approval within 15 minutes -> layer 3
	if req.TTLSeconds > 0 {
		ttl = time.Duration(req.TTLSeconds) * time.Second
	}
	b := make([]byte, 24)
	_, _ = rand.Read(b)
	token := "apr-" + hex.EncodeToString(b)
	if err := a.store.InsertProposal(r.Context(), token, req.RunID, req.ScenarioID, req.ActionID, req.Target, ttl); err != nil {
		writeErr(w, 500, err)
		return
	}
	a.store.Event(r.Context(), req.RunID, req.ScenarioID, "proposal", "ai", map[string]any{"action_id": req.ActionID, "target": req.Target, "diagnosis": req.Diagnosis, "token_suffix": token[len(token)-6:]})
	if req.Approved {
		by := req.ApprovedBy
		if by == "" {
			by = "unspecified"
		}
		_ = a.store.ApproveProposal(r.Context(), token, by)
		a.store.Event(r.Context(), req.RunID, req.ScenarioID, "approval", by, map[string]any{"action_id": req.ActionID, "token_suffix": token[len(token)-6:]})
	}
	writeJSON(w, 201, map[string]any{"token": token, "expires_in_s": ttl.Seconds(), "approved": req.Approved})
}

// GET /proposals/{token}: the HITL bot reads the decision state (approval may arrive through this API instead of the
// Discord button; the bot mirrors it into its message instead of letting the message expire, campaign 3/4 2026-10-08).
func (a *App) handleProposalGet(w http.ResponseWriter, r *http.Request) {
	p, err := a.store.GetProposal(r.Context(), r.PathValue("token"))
	if err != nil {
		writeErr(w, 404, errors.New("unknown proposal"))
		return
	}
	writeJSON(w, 200, map[string]any{"token": p.Token, "run_id": p.RunID, "scenario_id": p.ScenarioID, "action_id": p.ActionID,
		"approved": p.ApprovedAt != nil, "approved_at": p.ApprovedAt, "approved_by": p.ApprovedBy, "executed": p.ExecutedAt != nil, "executed_at": p.ExecutedAt, "expires_at": p.ExpiresAt})
}

// POST /proposals/{token}/approve: the HITL bot records the human decision (design 6.5 step 4). The proposal was
// registered at diagnosis time, so MTTA = approval - proposal (design 5.4) measures the real waiting time.
func (a *App) handleProposalApprove(w http.ResponseWriter, r *http.Request) {
	token := r.PathValue("token")
	var req struct {
		ApprovedBy string `json:"approved_by"`
	}
	_ = json.NewDecoder(r.Body).Decode(&req)
	if req.ApprovedBy == "" {
		req.ApprovedBy = "unspecified"
	}
	p, err := a.store.GetProposal(r.Context(), token)
	if err != nil {
		writeErr(w, 404, errors.New("unknown proposal"))
		return
	}
	switch {
	case p.ApprovedAt != nil:
		writeErr(w, 409, errors.New("proposal already approved"))
		return
	case time.Now().After(p.ExpiresAt):
		writeErr(w, 410, errors.New("proposal expired"))
		return
	}
	if err := a.store.ApproveProposal(r.Context(), token, req.ApprovedBy); err != nil {
		writeErr(w, 500, err)
		return
	}
	a.store.Event(r.Context(), p.RunID, p.ScenarioID, "approval", req.ApprovedBy, map[string]any{"action_id": p.ActionID, "token_suffix": token[len(token)-6:]})
	writeJSON(w, 200, map[string]any{"token": token, "approved": true, "approved_by": req.ApprovedBy})
}

// POST /proposals/{token}/reject: recorded as a note event (kind list of design 5.3); the token stays unapproved.
func (a *App) handleProposalReject(w http.ResponseWriter, r *http.Request) {
	token := r.PathValue("token")
	var req struct {
		RejectedBy string `json:"rejected_by"`
		Reason     string `json:"reason"`
	}
	_ = json.NewDecoder(r.Body).Decode(&req)
	p, err := a.store.GetProposal(r.Context(), token)
	if err != nil {
		writeErr(w, 404, errors.New("unknown proposal"))
		return
	}
	a.store.Event(r.Context(), p.RunID, p.ScenarioID, "note", req.RejectedBy, map[string]any{"rejected": true, "action_id": p.ActionID, "reason": req.Reason, "token_suffix": token[len(token)-6:]})
	writeJSON(w, 200, map[string]any{"token": token, "rejected": true})
}