package agentapi

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
)

// Controller-driven escrow ceremony client methods (v0.127.0, agent ≥ v0.88.0). The claim call
// is the ONLY place the recovery code R crosses this client — its response body must never be
// logged (the shared helpers log path/status/duration only, never bodies) and the caller hands
// R straight to the wizard's claim XHR, nowhere else.

// EscrowPreflightItem mirrors one agent preflight checklist row.
type EscrowPreflightItem struct {
	ID     string `json:"id"`
	OK     bool   `json:"ok"`
	Detail string `json:"detail"`
}

// EscrowPreflightResponse mirrors GET /escrow/preflight.
type EscrowPreflightResponse struct {
	VMID  int                   `json:"vmid"`
	OK    bool                  `json:"ok"`
	Items []EscrowPreflightItem `json:"items"`
}

// EscrowPreflight fetches the agent's ceremony prerequisite checklist.
func (c *Client) EscrowPreflight(ctx context.Context) (EscrowPreflightResponse, error) {
	var out EscrowPreflightResponse
	body, err := c.get(ctx, "/escrow/preflight")
	if err != nil {
		return out, err
	}
	if err := json.Unmarshal(body, &out); err != nil {
		return out, fmt.Errorf("agentapi: decode /escrow/preflight: %w", err)
	}
	return out, nil
}

// EscrowCeremonyStartResponse mirrors the POST /escrow/ceremony 202 payload.
type EscrowCeremonyStartResponse struct {
	JobID string `json:"job_id"`
	Phase string `json:"phase"`
}

// EscrowCeremonyStart triggers the agent's detached root ceremony job. Status-aware: the HTTP
// status is returned so the caller can map the agent's 409 (a ceremony already running) to its
// own house-style refusal.
func (c *Client) EscrowCeremonyStart(ctx context.Context) (EscrowCeremonyStartResponse, int, error) {
	var out EscrowCeremonyStartResponse
	env, status, err := c.postWithStatus(ctx, "/escrow/ceremony", struct{}{})
	if err != nil {
		return out, status, err
	}
	if err := refusalError("/escrow/ceremony", status, env); err != nil {
		return out, status, err
	}
	if err := json.Unmarshal(env.Data, &out); err != nil {
		return out, status, fmt.Errorf("agentapi: decode /escrow/ceremony: %w", err)
	}
	return out, status, nil
}

// EscrowCeremonyStatusResponse mirrors GET /escrow/ceremony/status — the NON-SECRET job view
// (R is structurally absent from the agent's payload).
type EscrowCeremonyStatusResponse struct {
	Phase             string  `json:"phase"` // none | running | done | failed | unclaimed_void
	JobID             string  `json:"job_id"`
	KeyFingerprint    string  `json:"key_fingerprint"`
	EntropyBits       float64 `json:"entropy_bits"`
	ResticPwSealed    bool    `json:"restic_pw_sealed"`
	Uploaded          bool    `json:"uploaded"`
	Claimable         bool    `json:"claimable"`
	Claimed           bool    `json:"claimed"`
	ClaimExpiresInSec int     `json:"claim_expires_in_sec"`
	Detail            string  `json:"detail"`
}

// EscrowCeremonyStatus polls the ceremony job.
func (c *Client) EscrowCeremonyStatus(ctx context.Context) (EscrowCeremonyStatusResponse, error) {
	var out EscrowCeremonyStatusResponse
	body, err := c.get(ctx, "/escrow/ceremony/status")
	if err != nil {
		return out, err
	}
	if err := json.Unmarshal(body, &out); err != nil {
		return out, fmt.Errorf("agentapi: decode /escrow/ceremony/status: %w", err)
	}
	return out, nil
}

// EscrowCeremonyClaim performs the ONE-SHOT R claim. Returns the recovery code + the agent's
// HTTP status (410 = already claimed / expired — the wizard's void state). The code must never
// be logged, persisted, or placed anywhere but the claim XHR response; the error path carries
// the agent's reason text, never the code.
func (c *Client) EscrowCeremonyClaim(ctx context.Context) (string, int, error) {
	env, status, err := c.postWithStatus(ctx, "/escrow/ceremony/claim", struct{}{})
	if err != nil {
		return "", status, err
	}
	if status == http.StatusGone {
		return "", status, fmt.Errorf("agentapi: POST /escrow/ceremony/claim: gone (claimed or expired)")
	}
	if err := refusalError("/escrow/ceremony/claim", status, env); err != nil {
		return "", status, err
	}
	var out struct {
		RecoveryCode string `json:"recovery_code"`
	}
	if err := json.Unmarshal(env.Data, &out); err != nil {
		return "", status, fmt.Errorf("agentapi: decode /escrow/ceremony/claim: %w", err)
	}
	if out.RecoveryCode == "" {
		return "", status, fmt.Errorf("agentapi: /escrow/ceremony/claim returned no code")
	}
	return out.RecoveryCode, status, nil
}

// RecoverOffsiteRepoPassword asks the agent to open this host's hub-held sealed bundle with the
// customer's recovery code and return ONLY the offsite restic repository password, plus its sha256
// (R-199, agent >= v0.125.0).
//
// R CROSSES HERE, AND NOWHERE ELSE IN THIS DIRECTION. It travels in the request body over the pinned
// local-API channel (the operator's 2026-08-04 acceptance) and is not retained by this client. The
// shared POST helper logs path/status/duration and never bodies — do not add a body log, on either
// the request or the response side: the request carries R and the response carries the password.
func (c *Client) RecoverOffsiteRepoPassword(ctx context.Context, recoveryCode string) (password, sha256hex string, err error) {
	env, status, perr := c.postWithStatus(ctx, "/escrow/recover-offsite-password",
		map[string]string{"recovery_code": recoveryCode})
	if perr != nil {
		return "", "", perr
	}
	// R-224: this route's refusal keeps its STATUS as a value. `refusalError` flattens status into a
	// sentence, and a sentence is not something a caller can branch on — which is exactly how a failed
	// fetch and a wrong recovery code came to produce one customer-facing message.
	if status < 200 || status > 299 || !env.OK {
		return "", "", &RecoveryRefusal{Status: status, Reason: truncateErr(env.Error, 300)}
	}
	var out struct {
		ResticRepoPassword string `json:"restic_repo_password"`
		ResticPwSHA256     string `json:"restic_pw_sha256"`
	}
	if uerr := json.Unmarshal(env.Data, &out); uerr != nil {
		return "", "", fmt.Errorf("agentapi: decode /escrow/recover-offsite-password: %w", uerr)
	}
	if out.ResticRepoPassword == "" || out.ResticPwSHA256 == "" {
		return "", "", fmt.Errorf("agentapi: the agent returned an empty recovery result")
	}
	return out.ResticRepoPassword, out.ResticPwSHA256, nil
}

// ── R-224 — CLASSIFYING A FAILED UNLOCK ─────────────────────────────────────────────────────────
//
// CAMPAIGN-11 measured what happens without this. On 2026-08-05, with a CORRECT current recovery
// code: the hub firewalled off returned the customer "this code does not open your package" in
// 0.0556 s, and this agent stopped returned the same in 0.0299 s — against ~1.0 s for a genuine
// unseal. Neither attempted one. The failure path had exactly two branches, both of them statements
// about the customer's code, and `rerr` was never inspected.
//
// The rule this type exists to enforce: **the customer is blamed only after a real attempt refused
// their code.** Everything else — including anything we cannot classify — says something else.

// RecoveryRefusal is the agent's refusal of an unlock, carrying the STATUS as a value so callers
// classify on it rather than on the sentence. The message keeps `refusalError`'s shape so operator
// logs read as they did.
type RecoveryRefusal struct {
	Status int
	Reason string
}

func (e *RecoveryRefusal) Error() string {
	reason := e.Reason
	if reason == "" {
		reason = "(no reason in agent response)"
	}
	return fmt.Sprintf("agentapi: POST /escrow/recover-offsite-password: HTTP %d: %s", e.Status, reason)
}

// RecoveryFailure is what went wrong, as far as it can be known.
type RecoveryFailure int

const (
	// RecoveryUnknown — the cause could not be determined. **The safe default**, and deliberately the
	// zero value: a new status, a transport shape nobody anticipated, or an agent too old to
	// distinguish fetch from refusal all land here, and none of them may blame the customer.
	RecoveryUnknown RecoveryFailure = iota
	// RecoveryHubUnreachable — the agent answered, and it could not FETCH the sealed package: the hub
	// refused, was unreachable, or recovery is not configured on this agent. **The code was not used.**
	RecoveryHubUnreachable
	// RecoveryAskedAndRefused — the bundle was fetched and the code did not open it. The ONLY class
	// from which the customer may be told to check their typing.
	RecoveryAskedAndRefused
	// RecoveryNoBundle — the hub holds no sealed package for this host at all.
	RecoveryNoBundle
	// RecoveryBundleTooOld — the bundle opened but predates the repository-password field.
	RecoveryBundleTooOld
	// RecoveryAgentUnreachable — the machine's own in-house service never answered, so there is no
	// agent verdict at all. **The code was not used.** Distinct from RecoveryHubUnreachable because
	// it is a different fault, with different words and a different remedy.
	RecoveryAgentUnreachable
)

// ClassifyRecoveryFailure maps an unlock error to its class, from the VALUE and never the text.
//
// ⚠ `trustRefusal` is the agent-version gate and it is not optional. An agent older than v0.126.0
// answers **400 for BOTH** a fetch failure and a wrong code, so a 400 from one cannot be read as
// "the code was refused" — it means "one of two things, and we cannot tell which". Pass false there
// and the 400 degrades to RecoveryUnknown, which is neutral. That degradation is the point: it is
// safe, it is silent, and it heals itself when the agent updates.
func ClassifyRecoveryFailure(err error, trustRefusal bool) RecoveryFailure {
	if err == nil {
		return RecoveryUnknown
	}
	var ref *RecoveryRefusal
	if !errors.As(err, &ref) {
		// Not a refusal at all — the request never produced an agent verdict (dial failure, TLS,
		// timeout, or the channel could not be built). The machine could not even ASK its own service,
		// which is a different sentence from "the hub was unreachable" and a different thing to fix.
		return RecoveryAgentUnreachable
	}
	switch ref.Status {
	case http.StatusBadGateway, http.StatusServiceUnavailable, http.StatusGatewayTimeout:
		// 502 is agent >= v0.126.0's "the sealed bundle could not be fetched". 503 is its
		// "recovery is not configured on this agent (no hub client)". Neither used the code.
		return RecoveryHubUnreachable
	case http.StatusNotFound:
		return RecoveryNoBundle
	case http.StatusConflict:
		return RecoveryBundleTooOld
	case http.StatusBadRequest:
		if trustRefusal {
			return RecoveryAskedAndRefused
		}
		return RecoveryUnknown
	default:
		return RecoveryUnknown
	}
}

// String names the class for the operator log. The customer never sees these words.
func (f RecoveryFailure) String() string {
	switch f {
	case RecoveryHubUnreachable:
		return "hub-unreachable"
	case RecoveryAgentUnreachable:
		return "agent-unreachable"
	case RecoveryAskedAndRefused:
		return "asked-and-refused"
	case RecoveryNoBundle:
		return "no-bundle"
	case RecoveryBundleTooOld:
		return "bundle-too-old"
	default:
		return "unknown"
	}
}