package roominfotree

import (
	"strings"

	"github.com/hashicorp/go-version"
	"github.com/matrix-org/gomatrixserverlib/fclient"
)

// Gets the maximum supported room version for the given server-version-pair.
func getMaxRoomVersion(serverVersionInfo fclient.Version) string {
	// Use only the first part of the version string as sometimes there are suffixes after a space, like " (<commit>)", which then can't be parsed.
	serverVersion, err := version.NewVersion(strings.Split(serverVersionInfo.Server.Version, " ")[0])
	if err != nil {
		return "unknown"
	}

	switch serverVersionInfo.Server.Name {
	case "Conduit":
		// https://conduit.rs/
		// https://conduit.rs/changelog/
		// https://gitlab.com/famedly/conduit
		switch {
		// https://conduit.rs/changelog/#v0-10-8-2025-08-11
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("0.10.8"))):
			return "v12"
		// https://conduit.rs/changelog/#v0-7-0-2024-04-25
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("0.7.0"))):
			return "v11"
		// https://conduit.rs/changelog/#v0-5-0-2022-12-21
		// Includes MR 400:
		// https://gitlab.com/famedly/conduit/-/merge_requests/400/commits
		// MR 400 includes a commit, which specifies v10 as stable.
		// https://gitlab.com/famedly/conduit/-/commit/1e1a144dfa98429ef9f02d16045796b73013830d
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("0.5.0"))):
			return "v10"
		// https://conduit.rs/changelog/#v0-4-0-2022-06-23
		// Includes MR 257:
		// https://gitlab.com/famedly/conduit/-/merge_requests/257/commits
		// MR 257 includes a commit, which specifies added support v7 to v9.
		// https://gitlab.com/famedly/conduit/-/commit/0ae39807a478370a769217d01fa33514299a2b35
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("0.4.0"))):
			return "v9"
		// https://conduit.rs/changelog/#v0-2-0-2021-09-01
		default:
			return "v6"
		}
	case "conduwuit", "Conduwuit":
		// Using continuwuitys source (history) as a reference:
		// https://forgejo.ellis.link/continuwuation/continuwuity

		// History from first commit on "continuwuity":
		// https://forgejo.ellis.link/continuwuation/continuwuity/commits/commit/e054a56b3286a6fb3091bedd5261089435ed26d1
		// Last commit on "conduwuit"/"Conduwuit":
		// https://forgejo.ellis.link/continuwuation/continuwuity/src/commit/d8311a5ff672fdc4729d956af5e3af8646b0670d
		// Last version was "0.5.0":
		// https://forgejo.ellis.link/continuwuation/continuwuity/src/commit/d8311a5ff672fdc4729d956af5e3af8646b0670d/Cargo.toml

		// Matching both "conduwuit" and "Conduwuit" as the capitalization got changed.
		// https://forgejo.ellis.link/continuwuation/continuwuity/commit/5b5ccba64e3d36a9235f4e0d449f40d859046dad

		switch {
		// Since the version went from "0.7.0-<something>" to "0.3.0" and the last version was "0.5.0", give all versions greater than "0.7.0" a lower max room version.
		// https://forgejo.ellis.link/continuwuation/continuwuity/commit/af0b81f5fb737d3550cf22fbcf8d8b8eb1947408
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("0.7.0"))):
			return "v10"
		// v11 support (shows there as included in tag "v0.3.0"):
		// https://forgejo.ellis.link/continuwuation/continuwuity/commit/223f05c922ea6f3085d386f0758df550459a25c3
		// Tag "v0.3.0":
		// https://forgejo.ellis.link/continuwuation/continuwuity/src/tag/v0.3.0/src/service/globals/mod.rs#L130
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("0.3.0"))):
			return "v11"
		// First version named "Conduwuit"/"conduwuit":
		// https://forgejo.ellis.link/continuwuation/continuwuity/commit/e71855cd0b59d9274e8528a4c1ee480f99006c3c
		// v10 support at first version named "Conduwuit"/"conduwuit":
		// https://forgejo.ellis.link/continuwuation/continuwuity/src/commit/e71855cd0b59d9274e8528a4c1ee480f99006c3c/src/service/globals/mod.rs#L187
		// And shows first version as "0.7.0-alpha+conduwuit-0.1.3":
		// https://forgejo.ellis.link/continuwuation/continuwuity/src/commit/e71855cd0b59d9274e8528a4c1ee480f99006c3c/Cargo.toml
		// Because of this versioning and the match on "0.7.0" before, this default should never match, but it is included for clarity.
		default:
			return "v10"
		}
	case "continuwuity":
		// https://continuwuity.org/
		// https://forgejo.ellis.link/continuwuation/continuwuity

		switch {
		// v12 support in "v0.5.0-rc.8".
		// https://forgejo.ellis.link/continuwuation/continuwuity/releases/tag/v0.5.0-rc.8
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("0.5.0-rc.8"))):
			return "v12"
		// First version named "continuwuity":
		// https://forgejo.ellis.link/continuwuation/continuwuity/commit/dc599db19c48ad3cbae15fc419c4a531d217ed05
		// v11 support at first version named "continuwuity":
		// https://forgejo.ellis.link/continuwuation/continuwuity/src/commit/dc599db19c48ad3cbae15fc419c4a531d217ed05/src/core/info/room_version.rs
		default:
			return "v11"
		}
	case "Dendrite":
		// https://github.com/element-hq/dendrite
		// https://element-hq.github.io/dendrite/
		// https://github.com/element-hq/dendrite/blob/main/CHANGES.md
		switch {
		// https://github.com/element-hq/dendrite/blob/v0.15.0/CHANGES.md#dendrite-0150-2025-08-12
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("0.15.0"))):
			return "v12"
		// https://github.com/matrix-org/dendrite/blob/v0.13.3/CHANGES.md#dendrite-0133-2023-09-28
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("0.13.3"))):
			return "v11"
		// https://github.com/matrix-org/dendrite/blob/v0.8.7/CHANGES.md#dendrite-087-2022-06-01
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("0.8.7"))):
			return "v10"
		// https://github.com/matrix-org/dendrite/blob/v0.8.6/CHANGES.md#dendrite-086-2022-05-26
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("0.8.6"))):
			return "v9"
		// https://github.com/matrix-org/dendrite/blob/v0.8.6/CHANGES.md#dendrite-086-2022-05-26
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("0.8.6"))):
			return "v8"
		// https://github.com/matrix-org/dendrite/blob/v0.4.1/CHANGES.md#dendrite-041-2021-07-26
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("0.4.1"))):
			return "v7"
		// https://github.com/matrix-org/dendrite/blob/v0.1.0/CHANGES.md#dendrite-010-2020-10-08
		default:
			return "v6"
		}
	case "grapevine":
		// https://grapevine.computer.surgery/
		// https://gitlab.computer.surgery/matrix/grapevine

		// Grapevine was forked from Conduit 0.7.0, which supports v11.
		return "v11"
	case "Synapse":
		// If the version is a Synapse Pro one, check against known Synapse Pro versions first and then fallback to checking against regular Synapse versions.
		// https://element.io/server-suite/synapse-pro
		// https://docs.element.io/latest/element-server-suite-pro/release-notes/#ess-helm-pro-2581-2025-08-12
		if strings.Contains(serverVersion.String(), "pro") {
			switch {
			// https://docs.element.io/latest/element-server-suite-pro/release-notes/#ess-helm-pro-2581-2025-08-12
			// The release notes list the version as "v1.135.0-pro4", but versions in the wild show up as "1.135.0+pro.4".
			case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("1.135.0+pro.4"))):
				return "v12"
			}
		}

		// https://github.com/element-hq/synapse/
		// https://element-hq.github.io/synapse/latest/
		// https://github.com/element-hq/synapse/blob/develop/CHANGES.md
		// https://github.com/element-hq/synapse/blob/develop/docs/changelogs/
		switch {
		// https://github.com/element-hq/synapse/blob/v1.135.1/CHANGES.md#synapse-11351-2025-08-11
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("1.135.1"))):
			return "v12"
		// https://github.com/element-hq/synapse/blob/v1.89.0rc1/CHANGES.md#synapse-1890rc1-2023-07-25
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("1.89.0rc1"))):
			return "v11"
		// https://github.com/element-hq/synapse/blob/v1.64.0rc1/CHANGES.md#synapse-1640rc1-2022-07-26
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("1.64.0rc1"))):
			return "v10"
		// https://github.com/element-hq/synapse/blob/v1.42.0rc2/CHANGES.md#synapse-1420rc2-2021-09-06
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("1.42.0rc2"))):
			return "v9"
		// https://github.com/element-hq/synapse/blob/v1.40.0rc3/CHANGES.md#synapse-1400rc3-2021-08-09
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("1.40.0rc3"))):
			return "v8"
		// https://github.com/element-hq/synapse/blob/v1.37.0rc1/CHANGES.md#synapse-1370rc1-2021-06-24
		// https://github.com/matrix-org/synapse/pull/10167
		// https://github.com/matrix-org/synapse/pull/10167/files#diff-8e36e2fc4dec5d84357ee3d140ad223b66fb36e630c25bbb45382ca59cdb0f40
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("1.37.0rc1"))):
			return "v7"
		// https://github.com/element-hq/synapse/blob/v1.14.0rc1/CHANGES.md#synapse-1140rc1-2020-05-26
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("1.14.0rc1"))):
			return "v6"
		// https://github.com/element-hq/synapse/blob/v1.0.0rc1/CHANGES.md#synapse-100rc1-2019-06-07
		// https://github.com/matrix-org/synapse/pull/5354
		// https://github.com/matrix-org/synapse/pull/5354/files#diff-8e36e2fc4dec5d84357ee3d140ad223b66fb36e630c25bbb45382ca59cdb0f40
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("1.0.0rc1"))):
			return "v5"
		// https://github.com/element-hq/synapse/blob/v0.99.5rc1/CHANGES.md#synapse-0995rc1-2019-05-21
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("0.99.5rc1"))):
			return "v4"
		// https://github.com/element-hq/synapse/blob/v0.99.0rc1/CHANGES.md#synapse-0990rc1-2019-01-30
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("0.99.0rc1"))):
			return "v3"
		// https://github.com/element-hq/synapse/blob/v0.34.1rc1/CHANGES.md#synapse-0341rc1-2019-01-08
		// https://github.com/matrix-org/synapse/pull/4307
		// https://github.com/matrix-org/synapse/pull/4307/files#diff-32e0f096397b0e3545054c51c42b5be4f0db953083b60d76a047cb1618f6b877
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("0.34.1rc1"))):
			return "v2"
		default:
			return "v1"
		}
	case "Tuwunel":
		// https://github.com/matrix-construct/tuwunel

		switch {
		// v12 support in "v1.4.0".
		// https://github.com/matrix-construct/tuwunel/releases/tag/v1.4.0
		// "v1.4.0-rc" has v12 support already as well, but should also just return "1.4.0" for its version.
		// https://github.com/matrix-construct/tuwunel/commits/v1.4.0
		// https://github.com/matrix-construct/tuwunel/commits/v1.4.0-rc
		case serverVersion.GreaterThanOrEqual(version.Must(version.NewVersion("1.4.0"))):
			return "v12"
		default:
			// First version named "Tuwunel":
			// https://github.com/matrix-construct/tuwunel/commit/9b658d86b2f49d01ba8d2f5ae7f263a104e8f282#diff-d58f31e506570d0bcb7629251ec1b350c5dde4a205a338349f154f3fd3187e93
			// v11 support at first version named "Tuwunel":
			// https://github.com/matrix-construct/tuwunel/blob/9b658d86b2f49d01ba8d2f5ae7f263a104e8f282/src/core/info/room_version.rs
			return "v11"
		}
	default:
		return "unknown"
	}
}